import java.util.LinkedList;
import java.util.Queue;

/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: 17655
 * Date: 2025-02-25
 * Time: 12:09
 */
public class test1 {
    /**
     * LeetCode  岛屿数量
     */

    int[] dx = {0,0,-1,1};
    int[] dy = {1,-1,0,0};
    // 用于判断当前位置是否已经遍历过
    boolean[][] vis = new boolean[301][301];
    int m,n;

    public int numIslands(char[][] grid) {
        m = grid.length;
        n = grid[0].length;
        int ret = 0;
        for(int i=0;i<m;i++){
            for(int j=0;j<n;j++){
                if(grid[i][j]=='1' && !vis[i][j]){
                    ret++;
                    // 连接左右为1的岛屿
                    bfs(grid,i,j);
                }
            }
        }
        return ret;
    }

    public void bfs(char[][] grid,int i,int j ){
        Queue<int[]> q = new LinkedList<>();
        q.add(new int[]{i,j});
        vis[i][j] = true;
        while(!q.isEmpty()){
            int[] t = q.poll();
            int a = t[0],b=t[1];
            for(int k = 0;k<4;k++){
                int x = a+dx[k];
                int y = b+dy[k];
                if(x>=0 && x<m && y>=0 && y<n && grid[x][y]=='1' && !vis[x][y]){
                    q.add(new int[]{x,y});
                    vis[x][y] = true;
                }
            }
        }
    }
}
